Medical robotic systems such as telesurgical systems used in performing minimally invasive surgical procedures offer many benefits over traditional open surgery techniques, including less pain, shorter hospital stays, quicker return to normal activities, minimal scarring, reduced recovery time, and less injury to tissue. Consequently, demand for such medical robotic systems is strong and growing.
Examples of medical robotic systems include the da Vinci® Surgical System and the da Vinci® S™ Surgical System from Intuitive Surgical, Inc., of Sunnyvale, Calif. Each of these systems includes a surgeon's console, a patient-side cart, a high performance three-dimensional (“3-D”) vision system, and Intuitive Surgical's proprietary EndoWrist® articulating instruments, which are modeled after the human wrist. When added to the motions of manipulators holding the surgical instruments, these articulating instruments allow at least six degrees of freedom of motion to their end effectors, which is comparable to or even greater than the natural motions of open surgery.
In conventional medical robotic systems, each medical device such as a surgical tool or image capturing device is typically manipulated by a separate robotic arm and is directed to a surgical site within a patient through its own minimally invasive incision. When it is desirable to retract extraneous tissue in order to access a target tissue to perform a medical procedure, it may be a simple matter to employ an extra robotic arm or human assistant to manipulate a retractor, such as shown in FIGS. 1˜2, where instruments 101, 102 gain clear physical access and image capturing device 103 gains clear visible access to target tissue 104 by employing a conventional retractor 201 which is used to pull extraneous tissue 105 out of their way.
When only a single entry port is available for performing a medical procedure, however, retraction of extraneous tissue is not so simple a matter. First of all, the medical device in such case may be a surgical instrument that includes more than one surgical tool as well as possibly an image capturing device that are controllably extendable and manipulatable: out of a distal end of the surgical instrument. If the retractor is a separate tool, then trying to fit it through the same port as the surgical instrument is generally not feasible due to the limited size of the port (which may be an incision or a natural body orifice).
On the other hand, adding a retractor as an additional surgical tool to the single port entry surgical instrument so that the additional tool is also controllably extendable and manipulatable out of the distal end of the surgical instrument is also not generally feasible due again to the limited diameter of the single port entry which in turn, places a limit on the maximum diameter of the surgical instrument. Even if it were feasible to add the retractor as an additional tool to the surgical instrument, it may not be possible for the retractor to physically reach the tissue to be retracted while the other surgical tools are performing a medical procedure on the target tissue due to the physical coupling, of the tools of the surgical instrument. In addition, even if the retractor tool was able to reach the extraneous tissue and have sufficient available extension to move it out of the way, it may be difficult for the retractor to exert the necessary force to do so because of a lack of leverage in its construction.